34 Proceedings of Royal Society of Edinburgh. [sess. 
previously heated up to 60° C., the starch is converted completely 
into dextrine as rapidly as previously, hut only 28’4 per cent, of the 
possible maltose producible from the starch is formed, and this 
quantity is not increased by the addition of more of the weakened 
ferment. It would appear, from these and other experiments, that 
the successive stages in the conversion of the starch into maltose 
depend on different ferments, which are destroyed, perhaps through 
coagulation, at different temperatures. Little is known of the 
products which intervene between albumen and peptone, and 
nothing of the action which the various secretions exert upon them. 
Yet a complete knowledge of these, and of the action upon them of 
the various secretions which are poured into the alimentary canal, 
is essential to a proper understanding of the process. At present 
the action of a ferment is always tested on the unchanged albumen, 
usually egg albumen or fibrin, although, as is probably the case with 
the intestinal secretion, it may operate only in the later stages in 
the splitting up of the albumen. This may perhaps account for the 
want of action of this secretion upon the chief articles of food which 
so many observers have recorded. The products resulting from the 
action of the secretions on the different forms of albumen in raw 
and in cooked condition, — the nature and relative amount of the 
peptone and bye-products formed in each case, — still require more 
exact investigation. By a consideration of the relative amount of 
peptone yielded by each we should be able to form a much more 
accurate conception of its dietetic value. The nature and amount of 
the bye-products, and the effect, in this relation, of prolonged action 
of a secretion, as may frequently occur in gastric digestion, might be 
expected to throw much light on the effect of diet in such disorders 
of assimilation as gout. 
The enzyme function is, as we have seen, to be regarded as a 
higher development of a primordial function of the protoplasm, and 
we have now to consider the question as to whether the degree of 
development in each organism is a fixed invariable quantity or one 
subject to variation. It follows, from what has been already stated, 
that such external conditions as temperature, nature, and reaction of 
the medium affect its action ; we have still to mention here that 
Fliigge * has observed that organisms when grown without the 
* Die Mikro- Organismen, page 470, 1886. 
